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a9cb3959 HCE |
1 | /* |
2 | * Watchdog driver for Atmel AT32AP700X devices | |
3 | * | |
4 | * Copyright (C) 2005-2006 Atmel Corporation | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
bb133450 HCE |
9 | * |
10 | * | |
11 | * Errata: WDT Clear is blocked after WDT Reset | |
12 | * | |
13 | * A watchdog timer event will, after reset, block writes to the WDT_CLEAR | |
14 | * register, preventing the program to clear the next Watchdog Timer Reset. | |
15 | * | |
16 | * If you still want to use the WDT after a WDT reset a small code can be | |
17 | * insterted at the startup checking the AVR32_PM.rcause register for WDT reset | |
18 | * and use a GPIO pin to reset the system. This method requires that one of the | |
19 | * GPIO pins are available and connected externally to the RESET_N pin. After | |
20 | * the GPIO pin has pulled down the reset line the GPIO will be reset and leave | |
21 | * the pin tristated with pullup. | |
a9cb3959 HCE |
22 | */ |
23 | ||
24 | #include <linux/init.h> | |
25 | #include <linux/kernel.h> | |
26 | #include <linux/module.h> | |
27 | #include <linux/moduleparam.h> | |
28 | #include <linux/miscdevice.h> | |
29 | #include <linux/fs.h> | |
30 | #include <linux/platform_device.h> | |
31 | #include <linux/watchdog.h> | |
c37f2713 AM |
32 | #include <linux/uaccess.h> |
33 | #include <linux/io.h> | |
e75e6577 | 34 | #include <linux/spinlock.h> |
5a0e3ad6 | 35 | #include <linux/slab.h> |
a9cb3959 HCE |
36 | |
37 | #define TIMEOUT_MIN 1 | |
a9cb3959 | 38 | #define TIMEOUT_MAX 2 |
726c9f61 WVS |
39 | #define TIMEOUT_DEFAULT TIMEOUT_MAX |
40 | ||
41 | /* module parameters */ | |
42 | static int timeout = TIMEOUT_DEFAULT; | |
43 | module_param(timeout, int, 0); | |
44 | MODULE_PARM_DESC(timeout, | |
45 | "Timeout value. Limited to be 1 or 2 seconds. (default=" | |
46 | __MODULE_STRING(TIMEOUT_DEFAULT) ")"); | |
a9cb3959 | 47 | |
86a1e189 WVS |
48 | static bool nowayout = WATCHDOG_NOWAYOUT; |
49 | module_param(nowayout, bool, 0); | |
28401140 WVS |
50 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" |
51 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
52 | ||
a9cb3959 HCE |
53 | /* Watchdog registers and write/read macro */ |
54 | #define WDT_CTRL 0x00 | |
55 | #define WDT_CTRL_EN 0 | |
56 | #define WDT_CTRL_PSEL 8 | |
57 | #define WDT_CTRL_KEY 24 | |
58 | ||
59 | #define WDT_CLR 0x04 | |
60 | ||
bb133450 HCE |
61 | #define WDT_RCAUSE 0x10 |
62 | #define WDT_RCAUSE_POR 0 | |
63 | #define WDT_RCAUSE_EXT 2 | |
64 | #define WDT_RCAUSE_WDT 3 | |
65 | #define WDT_RCAUSE_JTAG 4 | |
66 | #define WDT_RCAUSE_SERP 5 | |
67 | ||
a9cb3959 | 68 | #define WDT_BIT(name) (1 << WDT_##name) |
c0ead7e0 | 69 | #define WDT_BF(name, value) ((value) << WDT_##name) |
a9cb3959 | 70 | |
c0ead7e0 | 71 | #define wdt_readl(dev, reg) \ |
a9cb3959 | 72 | __raw_readl((dev)->regs + WDT_##reg) |
c0ead7e0 | 73 | #define wdt_writel(dev, reg, value) \ |
a9cb3959 HCE |
74 | __raw_writel((value), (dev)->regs + WDT_##reg) |
75 | ||
76 | struct wdt_at32ap700x { | |
77 | void __iomem *regs; | |
e75e6577 | 78 | spinlock_t io_lock; |
a9cb3959 | 79 | int timeout; |
bb133450 | 80 | int boot_status; |
7e2a1498 | 81 | unsigned long users; |
a9cb3959 HCE |
82 | struct miscdevice miscdev; |
83 | }; | |
84 | ||
85 | static struct wdt_at32ap700x *wdt; | |
28401140 | 86 | static char expect_release; |
a9cb3959 HCE |
87 | |
88 | /* | |
89 | * Disable the watchdog. | |
90 | */ | |
c0ead7e0 | 91 | static inline void at32_wdt_stop(void) |
a9cb3959 | 92 | { |
7e2a1498 WVS |
93 | unsigned long psel; |
94 | ||
e75e6577 | 95 | spin_lock(&wdt->io_lock); |
7e2a1498 | 96 | psel = wdt_readl(wdt, CTRL) & WDT_BF(CTRL_PSEL, 0x0f); |
a9cb3959 HCE |
97 | wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0x55)); |
98 | wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0xaa)); | |
e75e6577 | 99 | spin_unlock(&wdt->io_lock); |
a9cb3959 HCE |
100 | } |
101 | ||
102 | /* | |
103 | * Enable and reset the watchdog. | |
104 | */ | |
c0ead7e0 | 105 | static inline void at32_wdt_start(void) |
a9cb3959 HCE |
106 | { |
107 | /* 0xf is 2^16 divider = 2 sec, 0xe is 2^15 divider = 1 sec */ | |
108 | unsigned long psel = (wdt->timeout > 1) ? 0xf : 0xe; | |
109 | ||
e75e6577 | 110 | spin_lock(&wdt->io_lock); |
a9cb3959 HCE |
111 | wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN) |
112 | | WDT_BF(CTRL_PSEL, psel) | |
113 | | WDT_BF(CTRL_KEY, 0x55)); | |
114 | wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN) | |
115 | | WDT_BF(CTRL_PSEL, psel) | |
116 | | WDT_BF(CTRL_KEY, 0xaa)); | |
e75e6577 | 117 | spin_unlock(&wdt->io_lock); |
a9cb3959 HCE |
118 | } |
119 | ||
120 | /* | |
121 | * Pat the watchdog timer. | |
122 | */ | |
c0ead7e0 | 123 | static inline void at32_wdt_pat(void) |
a9cb3959 | 124 | { |
e75e6577 | 125 | spin_lock(&wdt->io_lock); |
a9cb3959 | 126 | wdt_writel(wdt, CLR, 0x42); |
e75e6577 | 127 | spin_unlock(&wdt->io_lock); |
a9cb3959 HCE |
128 | } |
129 | ||
130 | /* | |
131 | * Watchdog device is opened, and watchdog starts running. | |
132 | */ | |
133 | static int at32_wdt_open(struct inode *inode, struct file *file) | |
134 | { | |
135 | if (test_and_set_bit(1, &wdt->users)) | |
136 | return -EBUSY; | |
137 | ||
138 | at32_wdt_start(); | |
139 | return nonseekable_open(inode, file); | |
140 | } | |
141 | ||
142 | /* | |
28401140 | 143 | * Close the watchdog device. |
a9cb3959 HCE |
144 | */ |
145 | static int at32_wdt_close(struct inode *inode, struct file *file) | |
146 | { | |
28401140 WVS |
147 | if (expect_release == 42) { |
148 | at32_wdt_stop(); | |
149 | } else { | |
150 | dev_dbg(wdt->miscdev.parent, | |
bb133450 | 151 | "unexpected close, not stopping watchdog!\n"); |
28401140 WVS |
152 | at32_wdt_pat(); |
153 | } | |
a9cb3959 | 154 | clear_bit(1, &wdt->users); |
28401140 | 155 | expect_release = 0; |
a9cb3959 HCE |
156 | return 0; |
157 | } | |
158 | ||
159 | /* | |
160 | * Change the watchdog time interval. | |
161 | */ | |
162 | static int at32_wdt_settimeout(int time) | |
163 | { | |
164 | /* | |
165 | * All counting occurs at 1 / SLOW_CLOCK (32 kHz) and max prescaler is | |
166 | * 2 ^ 16 allowing up to 2 seconds timeout. | |
167 | */ | |
168 | if ((time < TIMEOUT_MIN) || (time > TIMEOUT_MAX)) | |
169 | return -EINVAL; | |
170 | ||
c37f2713 AM |
171 | /* |
172 | * Set new watchdog time. It will be used when at32_wdt_start() is | |
173 | * called. | |
174 | */ | |
a9cb3959 HCE |
175 | wdt->timeout = time; |
176 | return 0; | |
177 | } | |
178 | ||
bb133450 HCE |
179 | /* |
180 | * Get the watchdog status. | |
181 | */ | |
182 | static int at32_wdt_get_status(void) | |
183 | { | |
184 | int rcause; | |
185 | int status = 0; | |
186 | ||
187 | rcause = wdt_readl(wdt, RCAUSE); | |
188 | ||
189 | switch (rcause) { | |
190 | case WDT_BIT(RCAUSE_EXT): | |
191 | status = WDIOF_EXTERN1; | |
192 | break; | |
193 | case WDT_BIT(RCAUSE_WDT): | |
194 | status = WDIOF_CARDRESET; | |
195 | break; | |
196 | case WDT_BIT(RCAUSE_POR): /* fall through */ | |
197 | case WDT_BIT(RCAUSE_JTAG): /* fall through */ | |
198 | case WDT_BIT(RCAUSE_SERP): /* fall through */ | |
199 | default: | |
200 | break; | |
201 | } | |
202 | ||
203 | return status; | |
204 | } | |
205 | ||
42747d71 | 206 | static const struct watchdog_info at32_wdt_info = { |
a9cb3959 | 207 | .identity = "at32ap700x watchdog", |
28401140 WVS |
208 | .options = WDIOF_SETTIMEOUT | |
209 | WDIOF_KEEPALIVEPING | | |
210 | WDIOF_MAGICCLOSE, | |
a9cb3959 HCE |
211 | }; |
212 | ||
213 | /* | |
214 | * Handle commands from user-space. | |
215 | */ | |
a6be8e5f AC |
216 | static long at32_wdt_ioctl(struct file *file, |
217 | unsigned int cmd, unsigned long arg) | |
a9cb3959 HCE |
218 | { |
219 | int ret = -ENOTTY; | |
220 | int time; | |
221 | void __user *argp = (void __user *)arg; | |
222 | int __user *p = argp; | |
223 | ||
c37f2713 | 224 | switch (cmd) { |
a9cb3959 HCE |
225 | case WDIOC_GETSUPPORT: |
226 | ret = copy_to_user(argp, &at32_wdt_info, | |
227 | sizeof(at32_wdt_info)) ? -EFAULT : 0; | |
228 | break; | |
bb133450 | 229 | case WDIOC_GETSTATUS: |
a9cb3959 HCE |
230 | ret = put_user(0, p); |
231 | break; | |
bb133450 HCE |
232 | case WDIOC_GETBOOTSTATUS: |
233 | ret = put_user(wdt->boot_status, p); | |
234 | break; | |
a9cb3959 HCE |
235 | case WDIOC_SETOPTIONS: |
236 | ret = get_user(time, p); | |
237 | if (ret) | |
238 | break; | |
239 | if (time & WDIOS_DISABLECARD) | |
240 | at32_wdt_stop(); | |
241 | if (time & WDIOS_ENABLECARD) | |
242 | at32_wdt_start(); | |
243 | ret = 0; | |
244 | break; | |
0c06090c WVS |
245 | case WDIOC_KEEPALIVE: |
246 | at32_wdt_pat(); | |
247 | ret = 0; | |
248 | break; | |
249 | case WDIOC_SETTIMEOUT: | |
250 | ret = get_user(time, p); | |
251 | if (ret) | |
252 | break; | |
253 | ret = at32_wdt_settimeout(time); | |
254 | if (ret) | |
255 | break; | |
256 | /* Enable new time value */ | |
257 | at32_wdt_start(); | |
258 | /* fall through */ | |
259 | case WDIOC_GETTIMEOUT: | |
260 | ret = put_user(wdt->timeout, p); | |
261 | break; | |
a9cb3959 HCE |
262 | } |
263 | ||
264 | return ret; | |
265 | } | |
266 | ||
28401140 WVS |
267 | static ssize_t at32_wdt_write(struct file *file, const char __user *data, |
268 | size_t len, loff_t *ppos) | |
a9cb3959 | 269 | { |
28401140 WVS |
270 | /* See if we got the magic character 'V' and reload the timer */ |
271 | if (len) { | |
272 | if (!nowayout) { | |
273 | size_t i; | |
274 | ||
275 | /* | |
276 | * note: just in case someone wrote the magic | |
277 | * character five months ago... | |
278 | */ | |
279 | expect_release = 0; | |
280 | ||
281 | /* | |
282 | * scan to see whether or not we got the magic | |
283 | * character | |
284 | */ | |
285 | for (i = 0; i != len; i++) { | |
286 | char c; | |
7944d3a5 | 287 | if (get_user(c, data + i)) |
28401140 WVS |
288 | return -EFAULT; |
289 | if (c == 'V') | |
290 | expect_release = 42; | |
291 | } | |
292 | } | |
293 | /* someone wrote to us, we should pat the watchdog */ | |
294 | at32_wdt_pat(); | |
295 | } | |
a9cb3959 HCE |
296 | return len; |
297 | } | |
298 | ||
299 | static const struct file_operations at32_wdt_fops = { | |
300 | .owner = THIS_MODULE, | |
301 | .llseek = no_llseek, | |
a6be8e5f | 302 | .unlocked_ioctl = at32_wdt_ioctl, |
a9cb3959 HCE |
303 | .open = at32_wdt_open, |
304 | .release = at32_wdt_close, | |
305 | .write = at32_wdt_write, | |
306 | }; | |
307 | ||
308 | static int __init at32_wdt_probe(struct platform_device *pdev) | |
309 | { | |
310 | struct resource *regs; | |
311 | int ret; | |
312 | ||
313 | if (wdt) { | |
314 | dev_dbg(&pdev->dev, "only 1 wdt instance supported.\n"); | |
315 | return -EBUSY; | |
316 | } | |
317 | ||
318 | regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
319 | if (!regs) { | |
320 | dev_dbg(&pdev->dev, "missing mmio resource\n"); | |
321 | return -ENXIO; | |
322 | } | |
323 | ||
a7960784 JH |
324 | wdt = devm_kzalloc(&pdev->dev, sizeof(struct wdt_at32ap700x), |
325 | GFP_KERNEL); | |
a9cb3959 HCE |
326 | if (!wdt) { |
327 | dev_dbg(&pdev->dev, "no memory for wdt structure\n"); | |
328 | return -ENOMEM; | |
329 | } | |
330 | ||
a7960784 | 331 | wdt->regs = devm_ioremap(&pdev->dev, regs->start, resource_size(regs)); |
47d17763 HCE |
332 | if (!wdt->regs) { |
333 | ret = -ENOMEM; | |
334 | dev_dbg(&pdev->dev, "could not map I/O memory\n"); | |
335 | goto err_free; | |
336 | } | |
bb133450 | 337 | |
e75e6577 | 338 | spin_lock_init(&wdt->io_lock); |
bb133450 HCE |
339 | wdt->boot_status = at32_wdt_get_status(); |
340 | ||
341 | /* Work-around for watchdog silicon errata. */ | |
342 | if (wdt->boot_status & WDIOF_CARDRESET) { | |
343 | dev_info(&pdev->dev, "CPU must be reset with external " | |
344 | "reset or POR due to silicon errata.\n"); | |
345 | ret = -EIO; | |
a7960784 | 346 | goto err_free; |
bb133450 HCE |
347 | } else { |
348 | wdt->users = 0; | |
349 | } | |
f1f5bda4 HCE |
350 | |
351 | wdt->miscdev.minor = WATCHDOG_MINOR; | |
352 | wdt->miscdev.name = "watchdog"; | |
353 | wdt->miscdev.fops = &at32_wdt_fops; | |
354 | wdt->miscdev.parent = &pdev->dev; | |
355 | ||
356 | platform_set_drvdata(pdev, wdt); | |
a9cb3959 | 357 | |
726c9f61 WVS |
358 | if (at32_wdt_settimeout(timeout)) { |
359 | at32_wdt_settimeout(TIMEOUT_DEFAULT); | |
a9cb3959 HCE |
360 | dev_dbg(&pdev->dev, |
361 | "default timeout invalid, set to %d sec.\n", | |
726c9f61 | 362 | TIMEOUT_DEFAULT); |
a9cb3959 HCE |
363 | } |
364 | ||
365 | ret = misc_register(&wdt->miscdev); | |
366 | if (ret) { | |
367 | dev_dbg(&pdev->dev, "failed to register wdt miscdev\n"); | |
321e3123 | 368 | goto err_free; |
a9cb3959 HCE |
369 | } |
370 | ||
28401140 WVS |
371 | dev_info(&pdev->dev, |
372 | "AT32AP700X WDT at 0x%p, timeout %d sec (nowayout=%d)\n", | |
373 | wdt->regs, wdt->timeout, nowayout); | |
a9cb3959 HCE |
374 | |
375 | return 0; | |
376 | ||
47d17763 | 377 | err_free: |
a9cb3959 HCE |
378 | wdt = NULL; |
379 | return ret; | |
380 | } | |
381 | ||
382 | static int __exit at32_wdt_remove(struct platform_device *pdev) | |
383 | { | |
384 | if (wdt && platform_get_drvdata(pdev) == wdt) { | |
28401140 WVS |
385 | /* Stop the timer before we leave */ |
386 | if (!nowayout) | |
387 | at32_wdt_stop(); | |
388 | ||
a9cb3959 | 389 | misc_deregister(&wdt->miscdev); |
a9cb3959 | 390 | wdt = NULL; |
a9cb3959 | 391 | } |
a9cb3959 HCE |
392 | return 0; |
393 | } | |
394 | ||
395 | static void at32_wdt_shutdown(struct platform_device *pdev) | |
396 | { | |
397 | at32_wdt_stop(); | |
398 | } | |
399 | ||
400 | #ifdef CONFIG_PM | |
401 | static int at32_wdt_suspend(struct platform_device *pdev, pm_message_t message) | |
402 | { | |
403 | at32_wdt_stop(); | |
404 | return 0; | |
405 | } | |
406 | ||
407 | static int at32_wdt_resume(struct platform_device *pdev) | |
408 | { | |
409 | if (wdt->users) | |
410 | at32_wdt_start(); | |
411 | return 0; | |
412 | } | |
97a2a2ea AM |
413 | #else |
414 | #define at32_wdt_suspend NULL | |
415 | #define at32_wdt_resume NULL | |
a9cb3959 HCE |
416 | #endif |
417 | ||
f37d193c KS |
418 | /* work with hotplug and coldplug */ |
419 | MODULE_ALIAS("platform:at32_wdt"); | |
420 | ||
a9cb3959 HCE |
421 | static struct platform_driver at32_wdt_driver = { |
422 | .remove = __exit_p(at32_wdt_remove), | |
a9cb3959 HCE |
423 | .suspend = at32_wdt_suspend, |
424 | .resume = at32_wdt_resume, | |
a9cb3959 HCE |
425 | .driver = { |
426 | .name = "at32_wdt", | |
427 | .owner = THIS_MODULE, | |
428 | }, | |
429 | .shutdown = at32_wdt_shutdown, | |
430 | }; | |
431 | ||
1cb9204c | 432 | module_platform_driver_probe(at32_wdt_driver, at32_wdt_probe); |
a9cb3959 | 433 | |
aeb0aea1 | 434 | MODULE_AUTHOR("Hans-Christian Egtvedt <egtvedt@samfundet.no>"); |
a9cb3959 HCE |
435 | MODULE_DESCRIPTION("Watchdog driver for Atmel AT32AP700X"); |
436 | MODULE_LICENSE("GPL"); | |
437 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |